Alloy



Patented Oct. 4, 1938 ALLOY Henry R. Kiepe, Newark, N. 3., assignmtoBaker & Company, Inc., a corporation sey of New Jer- No Drawing.Application January 29, 1938, Serial No. 187,660

4 Claims. (01. 15-172) This invention relates to alloys of whichpalladium constitutes the major portion, one object of the inventionbeing to provide such an alloy which shall be harder than palladium,which can be highly polished, which can be easily worked into variousshapes, which shall have an attractive white color and shall be highlyresistant to oxidation, tarnish or other discoloration.

Palladium is known to be a relatively soft metal in both the annealedand the hard-worked state. It is also known that palladium can behardened by alloying it with ruthenium. However, the structure of alloysof palladium and ruthenium is not good; there is a tendency of theconstituents to resist the formation of a uniform crystalline structure,as the result of which the harder or richer ruthenium particles appearas streaks in the alloy, especially when the alloy is polished.Moreover, the palladiumruthenium alloys become practically unworkable ifthey contain over ten percent (10%) of ruthemum.

I have discovered that these deficiencies of the palladium-rutheniumalloys can be eliminated or diminished by the addition of copper to thepalladium and ruthenium. The copper acts as a mutual solvent for thepalladium and ruthenium, and thereby makes possible an alloy of uniformstructure. These alloys containing substantially palladium, rutheniumand copper also are hard-but not brittle, will take a high polish,resist oxidation and tarnish, and are easily workable. Therefore, theycan be made into many different articles of simple or complicatedshapes, for example articles of jewelry, pen nibs, electric switchcontacts, spinnerets used for manufacture of artificial silk, electricalresistance wires, dental and orthodontic appliances, and so forth.

As above stated, the alloy of the invention is predominantly palladium,the remainder being substantially ruthenium and copper. The proportionsof the constituent metals may be widely varied. The amount ofpalladium,- preferably, is from eighty percent to ninety-eight percent(98%). The ruthenium content may be as low as five-tenths of one percent(0.5%) or as high as fifteen percent (15%), but preferably lies withinthe range of from one percent (1%) to ten percent (10%). The content ofthe copper may similarly vary from five-tenths of one percent (0.5%) tofifteen percent preferably the variations lie within the range of fromone percent (1%) to ten percent (10%). The particularly preferred alloycomprises sub- (15%). but" stantially about ninety-three and one-halfpercent (93.5%) of palladium, about three and onehalf percent (3.5%) ofruthenium and about three percent (3%) of copper.

A striking feature of the invention is the discovery that thedeficiencies of the known palladium and ruthenium alloys can be overcomeor reduced by the addition of copper to the palladium and the ruthenium.This remarkable effect of copper is demonstrated particularly inconnection with the hardness of the alloys. Heretofore, alloys ofpalladium and ruthenium have been considered to be unworkable when morethan ten percent (10%) of ruthenium is present. Copper is generallyconsidered to be a hardening agent, and ordinarily the addition of ahardening element to an alloy renders the resultant alloy still morediflicult to work. However, I have discovered that the addition ofcopper to palladium-ruthenium alloys, makes the resultant alloy moreeasily workable, even to the extent of making workable such an alloycontaining 'as much as fifteen percent (15%) of ruthenium.

The following table illustrates the hardness of various alloys lyingwithin the scope of the invention.

Brinnell hardness (baby Brinnell 2 mm. ball, kg. Pd Ru Cu PercentPercent Percent Annealed Hard 000 0. 15 worked minutes 98 l 1 109 59 954 l 158 89 93.5 4.5 2 107 95 2 3 123 74 93.5 3.5 3 163 90 80 l0 10 227166 70 15 15 237 152. 84.5 0.5 15 178 101 84.5 15 0.5 229 198 is capableof being highly polished, which is re--v sistant to oxidation andtarnish, and which is easily workable into many different articlesrequiring all or any of the aesthetic, physical, metallurgical andchemical properties hereinbefore described.

half percent (93.5%) palladium, three and one- 10 half percent (3.5%)ruthenium and three percent (3%) copper.

3. An alloy containing-from one percent 1%) to ten percent (10%)ruthenium, andirom one percent (1%) to ten percent (10%) copper, the

remainder being palladium.

4. An alloy of palladium, ruthenium and copper wherein there is fromeighty percent (80%) to ninety-eight percent (98%) 01 palladium, the,

remainder consisting of approximately equal amounts of ruthenium andcopper.

HENRY R. KIEPE.

